I'd like to rig the unit up to run off bike power stepping down the bike voltage to 3V.

Click to expand...

It's hard to imagine why you would need this. The SPOT isn't like a typical GPS unit that can run a set of batteries down in a matter of a day or two. The SPOT batteries will last for weeks of continuous use. Plus, with the wired connection, you loose the option to walk away from your bike with the SPOT in hand. And, when you're in the middle of nowhere, and your electrical system (and thereby the SPOT) dies on you, leaving you stranded, that may be the exact time when you need the SPOT to work. Add to that the fair chance that you'll fry the SPOT while testing the regulator circuit, and it seems you're at high risk of the SPOT not being able to do what it was intended to do.

If you still think it's a good idea, all sorts of voltage regulators are available at www.digikey.com

It's hard to imagine why you would need this. The SPOT isn't like a typical GPS unit that can run a set of batteries down in a matter of a day or two. The SPOT batteries will last for weeks of continuous use.

Click to expand...

I agree. Not necessary. I forget what a pair of AA batteries is rated for in SPoT -- I think I recall seeing 2,000 transmissions in there somewhere. Well, let's say the real number is half that. That's roughly 10,000 minutes of operating time in tracking mode, or about 14 12-hr days in the saddle. Going to an external DC source seems...not necessary. Take an extra pair of batteries if you're really, really worried.

Thanks for the replies about the battery life stuff. It sounds pretty reasonable to use batteries. I guess I was just thinking of the benefits of being able to plug it in and forget it, forever.

It's pretty easy to build a +3V regulated "supply". A small 5v regulator and a 2 resistor voltage divider. These are small enough that you can build it and heat shrink it right on the power cord so all you need to do is plug it into a bike or car voltage source. I did something similar for my MP3 Player and plug it into the USB port. Now I can run the back light all the time with no battery concerns.

On another note, I did a couple of quick searches and haven't seen any mention here about jasonjonas' SPOT Trip Manager (STM) web site. He uses the OK and Help messages to implement tracking on sharable Google map pages that are pretty slick. Way better that the Star-Traxx implementation, as far as I can see. http://www.jasonjonas.org/spot/.

...On another note, I did a couple of quick searches and haven't seen any mention here about jasonjonas' SPOT Trip Manager (STM) web site. He uses the OK and Help messages to implement tracking on sharable Google map pages that are pretty slick. Way better that the Star-Traxx implementation, as far as I can see. http://www.jasonjonas.org/spot/.

Click to expand...

Check out SpoT's implementation of the same thing. It's in beta, and not perfect...yet, but seems reasonable as a first try. I've not used it in a while, so I may be fuzzy on the details, but basically you get a public page showing your tracking or check-in locations for the previous 24-hrs that you can provide for your family and friends. Details (with inevitable commentary) earlier in this thread.

I just read this. I think this means SPOT coverage has just expanded to the areas listed. Hopefully this type of upgrade will continue across the globe. Lots of us need Argentina fully covered by January!

Globalstar Satellite Data Coverage Expands: Globalstar, Inc. has expanded its satellite Simplex data coverage to include all of Alaska, the Aleutian Islands and the surrounding maritime regions including the Gulf of Alaska and portions of both the north Pacific and south Arctic Oceans. The expanded Simplex data coverage, which is available on six continents, is the result of an applique hardware installation and software upgrades at the Globalstar satellite gateway or ground station located in Wasilla, Alaska.